I know what windows and orphans are Back in the days when I used LaTeX quite extensively, I ventured into the type setting field which was quite interesting.

I disagree, and so does LaTeX for example. Both, Nook and LaTeX seem to aim at preventing ragged page ends by (subtly) increasing the spacing between paragraphs or other objects on your page in order to avoid widows and orphans. But that, sometimes, was too aggressive and I ended up with gaps in the text flow that I thought disrupting.

It doesn't really matter to me on an eReader device, to be honest. This should be a user setting, not an eBook setting. It does matter for printed books though, but that's not what I'm doing here anyway

With widows and orphans both set to zero, ADE does not monkey with line spacing between paragraphs. That is what you said widows and orphans (set to zero) would do and they won't do that.